Electromagnetic relay



June 6, 1950 s. H. TowNL-:R ETAL 2,510,157

ELECTROMAGNETIC RELAY Filed July 25. 1944 HG2. gm'

Patented June 6, 1950 ELECTROMAGNETIC RELAY Stanley Herbert Towner and Percy Arthur Childs, London, England, assignors, by mesne assignments, to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application July 25, 1944, Serial No. 546,545 In Great Britain July 7, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires July 7, 1963 9 Claims. 1

This invention relates to electromagnetic relays.

Among the objects of the invention is that of reducing the deleterious effects upon the relay and its operation of mechanical vibration or shock. It has been found with electromagnetic relays of known types that the stability and operation of their contacts are adversely aected by mechanical vibration or shock, possibly due to the production of relatively large linear accelerations of the movable parts, and a design is required in which such effects are of negligible magnitude. Whether or not the above tentative explanation is correct, it has certainly been found that designs in accordance with the present invention do show improvement in these respects.

Another important object of the invention is to provide a novel and advantageous electromagnetic relay.

A further object of the invention is to provide a novel and advantageous electromagnet-andarmature device.

This invention includes an electromagnetic relay comprising a substantially flat armature pivoted near its center and arranged so that the operating force and contact load are applied on opposite sides of the pivot, and so that the gravitational moments of the masses of the moving vparts are substantially balanced about the pivot.

The invention will now be described with reference to the accompanying drawing, which shows by way of example one embodiment. In the drawing:

Fig. 1 is a view in side elevation;

Fig. 2 is a left-hand end view;

Fig. 3 is a right-hand end view;

Fig. 4 is a top-plan view with the contactspring pile-up removed to expose the armature; and

Fig. 5 is a view in longitudinal central section.

In the drawing is shown the usual relay winding II mounted upon a soft-iron core I2 of which the forward projecting end is turned up and then back to form a pole-piece I3 with its flat uppermost surface constituting the pole-face. Tightly fitting over, and preferably welded to, the rearward projecting end of the core I2 is a yoke I4 extending upwardly and forwardly along the top of the winding II to within a short distance of the pole-piece I3. The armature, which will be more particularly described, is shown at I5 bridging the gap be- "tween yoke I4 and pole-piece I3: the contactspring pile-up is shown at I6.

Referring more particularly to Figs. 1, 4 and 5,

it will be seen that the armature I5 is almost but not quite flat when viewed edgewise and that it lies in a plane substantially parallel with those of the contact-springs of the pile-up I6. A D-shaped opening is cut away in the rearward half, leaving a frame-like tail I1 that normally rests upon the supporting stop 22, for engagement with the lifting pins I8 on the pile-up I6. This tail is bent slightly upwards with respect to the plane of the remainder of the armature. Of the solid forward half of the armature, the most rearward part lies between the flanks of the D-shaped tail-frame and terminates in a knife edge I9 which lies slightly below the level of the tail and which therefore is able to constitute the pivot for the armature as it rests upon the upper surface of the yoke I4 with its solid forward half overlying the pole-face on the piece I3. Energization of the coil II causes the forward end of the armature I5 to be attracted downwardly to the pole-piece I3, the armature turning about the edge I9 so that the tail I1 rises from the stop 22 and through the intermediary of the lifting pins I8 causes operation of the contacts of the pile-up I6. Thus the operating force and the contact load are applied on opposite sides of the pivot.

The armature pivots on its edge across almost the full width of the relay, making an iron to iron contact with the yoke which it overlaps to provide a low reluctance hinge joint.

The armature is permanently located in its correct position by means of light leaf springs 20. As shown there are two of these springs. formed integral with a single cross piece and. extending parallel with the longitudinal axis of.' the armature, that is at right angles to the pivotal axis I9. They thus underly the iianks: of the D-shaped tail-frame of the armature. At; their forward ends they are welded to the underside of the armature, and at their rearward ends they are welded to the top surface of the yoke I4. Beryllium-copper is a suitable material for the springs.

Preferably the dimensions of the armature locating springs are chosen so that the forces exerted by them on the armature over the full range of armature movement are small relative to those due to the contact springs in the pileup IE. The springs are not by themselves strong enough to perform the usual retractile function, and reliance must be placed primarily upon the resilience of the contact-springs, in the usual manner. However, the additional springs 2D may be biased so as to ensure that the knife edge on the armature seats always on the yoke, thus avoiding hammeringvupon the knife edge.

It is afe'ature of this;y invention LthattheY gravi-v tational rnoinentskof the masses of themovi'ng parts are substantially balanced about the DVO that there is substantially no resultant torquel that would cause improper operati-on or release of the armature.

The contact unit is xed to the magnet sysl tem by a single screw 2! passing througlx"they moulding,A acting as support of the Contact spring pileup i6, -into-thelryokefandiis located? atfthfe. forward endby twostepsv-in/ the mould-ing which tf'foverthe edge of the pole; face. This means that thepile-'up constitutes an `independent funt, ar'1d`\that,-in particular, its adjustment'can be carried out' before assembly with the remainderof the!V relay. Asindicated in Figs. l, 2 and 3, the moulding of`rv the contactspring. pile-up i6 has' a,-fvvidel forward portion above the ,pole-piece I3fanda narrower portion extending'rearward.n lyl between theV contact-springs which are clamped at the sides of said wide portion.r

'Ihe forward portion ofthe yoke i-li is set down slightlyA below the'poleface so that theti'gh-tening of thescrew Zipulls'the yokefparallel tothe pole" face,` thel registration being: controlled by the mouldingland-'beingv maintained by the pressure at the rear end:

The at'shape'of' the armature and its lo-f cation between:y the'winding and; core assembly below and the contact-springpile-up assembly above, affordsA the armature some measure of protection against mechanical contact'.

What is claimedfis:

l.Y In ran''electromagnetic device; the combination of apole-piece with a` hat contact surface and a second'poie-piece with-a contact surface inA alignment with said fiat contact surface, an armature lhaving twoar-ms, both saidy arms arranged above andextendingalong saidvk two pole pieces, one of= said arms; withY a hat: pole-piece bridging surface` and; at;v an end thereof a lknife edge pivot in the same plane as said bridging surface and adaptedtorest onlsaid. flat Contact surfaca; and the second of said armsnoffs'et out'- wardly from the. planeof*saidV bridging surface.

2. In anelectromagnetic device. the combi@- nation of aV pole-1piece withra Hat Contact surfacey and; a second,l pole-piece havingn a contact surface in alignment with said hat' contact sur'- face,` an armature having a flat 4p'ole-piek'ze bridging surface and at one end offthisfsur'face aknife edgev pivot resting on said'vfiat'vccntaot surface and bounded at one side by'theplane of said flat pole-piecefbridging surface."l

3. The combination according tc claim 2; including: means for maintaining. the knife' edge in position on thef flat cc'mt'ac'tV surface comprising a leaf springattached atv opposite sides 4of said pivot to said armatureand to said pole p'iec'e with theflat contact-surface. l v Y 4. In an electromagnetic device', the'com'bina- Vtionoiy a pole-piece with' a flat ccntactsurface and a second pole-piece having a contact surface, means Supporting said pole pieces for bringing :said contactfsurfaces into alignment and an armature having` a, flatpole-piece-bridging surface and at one end of the bridging surface a knife-edge pivot resting on said at contact surface and bounded at one side by the plane of said flat bridging surface.

`5. In'` anv electromagnetic device, the combination o'f'a pole-piece with a fiat contact surface and a secondpole-piece having a contact surface, and an armature arm having a fiat pole-piecebridging surface and at one end of the bridging surface a--kriifei edge pivot resting on said fiat contact surface and bounded at one side by the plane of said-nat bridging surface, and supportingmeans for bringing said contact surfaces into alignment and shielding said armature arm.

6i In" an electromagnetic device, the combination of a pole-piece with a hat Contact surface and a1 secondv pole-piece having. ,a Contact; in alignment with said flat contact suriace, `an armature khaving twoy arms, both said arms` arn ranged aboveand extending alongl said two y'pole pieces, one: of said armswith a iiat pole-piecebridging surface and a tongue providing an ex-y tension of said; hat bridging face and alsoA a knifev edge pivot resting on said fiat contact surface, andthesecond ofsaid arrnssvpresenting an actuatingl arm attached to the iirst armr and oisetI therefrom and from the knife edge pivot. y

7;. The combination according to claim 6Mincluding means for maintaining the knife, edge pivot. in operative position comprising Ya, leaf spring: attached toy said armature and to the pivot supporting pole piece, and means for swinging the armatureto. Open POStOnf t. v v.

- 8. The combination according' to claimV 6 wherein the material of said armature is-of uni'- form thicknessfrom end toend..v y

9,-In an electromagneticrelay, the combination of a pole face, an armature havingtwoarms andi pivotedgv atv an intermediate point thereof one arm being substantially flat and `having a central portion Wcut-out, a contact-spring pile-up comprising al moulding extending through the openingdened by the saidcut-out, means to secure said moulding iin-position on pole face and controlling meansfor said contactspringpile-up engaging Sayid Onepalmf t sfrANLEY HERBERT. TEQWNER- PERCY ARTHUR CHILDS.

REFERENCES CITED The followingreferences-,are of record in the le of this patenti:

UNITED STATES PATENTS ato'ri Oct." 14; 

